Silenus was a companion of the god of wine Dionysus in Greek mythology. He was much older than the satyrs, followers of the god, and had the characteristics of a horse rather than a goat. A group of Dionysus' followers was also named Sileni (plural), their most notable characteristic being that they were drunk. Eventually, the word was used as a name of the teacher and close companion of the god.

Silenus was always drunk and was either supported by satyrs or on a donkey. While drunk, it was believed that he acquired arcane knowledge and was able to predict the future. According to a myth, King Midas of Phrygia managed to catch Silenus when he was drunk by a fountain in order to learn his secrets. A different version has it that Silenus was lost in the region of Phrygia, and was eventually found by peasants who took him to the king. Midas welcomed him and treated him kindly, and Dionysus, wanting to repay for the kindness he showed towards Silenus, told him he would give him a reward; Midas asked for the ability to turn everything he touched into gold.